Implements the runtime backbone for TaskCreate/TaskGet/TaskList/TaskStop/
TaskUpdate/TaskOutput tool surface parity. Thread-safe (Arc<Mutex>) registry
supporting:
- Create tasks with prompt/description
- Status transitions (Created → Running → Completed/Failed/Stopped)
- Message passing (update with user messages)
- Output accumulation (append_output for subprocess capture)
- Team assignment (for TeamCreate orchestration)
- List with optional status filter
- Remove/cleanup
7 new unit tests covering all CRUD + error paths.
Next: wire registry into tool dispatch to replace current stubs.
5ea138e680